Lowell--help us help you! If you post a question, make sure you include a CREATE TABLE... statement and INSERT INTO... statement into that table to give the volunteers here representative data. with your description of the problem, we can provide a tested, verifiable solution to your question! asking the question the right way gets you a tested answer the fastest way possible!

because this seems a lot like homework, i only offered a partial SQL to help you think about the issue;this doesn't pass a syntax check but provides a couple of clues as to how to tackle the issue

SELECT * FROM (select row_number() over(partition by order by.....) As RW FROM SOMETABLE ) myAlias Where RW = 3

if you can show your work, and tell us what isn't working, we could help you understand the concepts behind solving the issue.

Lowell--help us help you! If you post a question, make sure you include a CREATE TABLE... statement and INSERT INTO... statement into that table to give the volunteers here representative data. with your description of the problem, we can provide a tested, verifiable solution to your question! asking the question the right way gets you a tested answer the fastest way possible!

My advice:INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.